In Advanced Video Coding (AVC), changing a quantization parameter (referred to as Delta Quantization Parameter (DQP)) is allowed at the macroblock level for better rate control and region-of-interest coding purposes. In the HEVC test Model (HM) 1.0, DQP is allowed at the Largest Coding Unit (LCU) level. The standard DQP syntax introduces difficulty in hardware decoding.
In the standard DQP syntax in HM:    Case I: If one LCU is not split into smaller coding units (CUs), and is coded in the SKIP mode, no DQP is signaled for that LCU.    Case II: otherwise, the DQP is signaled at the end of the LCU. FIG. 1 shows an exemplary LCU 100 with the DQP 102 at the end.
HEVC allows an LCU to be split into smaller CUs through quad-tree partitioning, and encodes each CU within an LCU in z-order and interleaves their mode and coefficients. An example is shown in FIG. 1, where M0, M1, . . . , M6 represent the mode information for CU0, CU1, . . . , CU6, and C0, C1, . . . , C6 represent the DCT coefficients of CU0, CU1, . . . , CU6. The standard DQP syntax has significant disadvantages. On one hand placing DQP at the end of an LCU could introduce delay in decoding, which means, when C0 is entropy-decoded, reconstruction of CU0 is not possible until the DQP value is read. This will significantly increase the length of a decoding pipeline. On the other hand, the DQP is unnecessarily sent with the standard syntax. For example, if the LCU is partitioned into multiple SKIP CUs, or if the coded block flag (cbf) is zero for every Transform Unit (TU) inside the LCU, then there are no non-zero coefficients in the current LCU so DQP is not needed. But the standard syntax still signals DQP, which is a waste of bits.